Field of the Invention
The invention relates to a device for the purpose of influencing the transfer of vibration between two units, one of which is mounted so that it can vibrate, and the other of which is mounted such that it can be damped, with a parallel circuit.
Description of the Prior Art
A device known as a dynamic anti-resonance force isolator is disclosed in U.S. Pat. No. 3,322,379, and serves to provide decoupling of vibration between a unit subjected to parasitic vibrations, and a unit that is to be damped with respect to the parasitic vibrations. In particular the device, by means of appropriate matching to the main frequency of excitation of the unit subjected to the parasitic vibrations, is able to isolate completely the unit that is to be damped with respect to the parasitic vibrations. For this purpose the device makes use of a mechanically driven pendulum as a force generator which is introduced in parallel to an elastically deformable support spring between the unit subjected to the parasitic vibrations and the unit that is to be damped. Such an anti-resonance force isolator arrangement of known art is schematically represented in FIG. 2. A unit 1 is mounted such that it can vibrate while being mounted opposite to a unit 2 that is to be damped. Thus the vibrating unit 1 represents a base plate, at whose center of gravity 1s an exciting force Fe acts, directed in one dimension and in two directions, which sets the unit 1 into vibration. In the interests of a clearer representation a one degree of freedom system is supposed, in which force components that are oriented in two directions act between the two units 1 and 2 just along or parallel to a single force axis. For the purpose of vibration isolation, or vibration reduction, an elastically deformable support spring 3 is provided between the vibrating unit 1 and the unit 2 that is to be damped. The spring forms a first force path K1, along which both static and dynamic force components are transferred. Parallel to the support spring 3, a force isolator, designed as a pendulum mechanism, is provided between the vibrating unit 1 and the unit 2 that is to be damped, by which inertial forces originating from the pendulum mechanism are introduced along a second force path K2 that is oriented in parallel to the first force path K1. To this end the force generator provides a lever 4, whose one end of the lever arm 41 is mounted such that it can rotate by a rotary bearing 5 about a first axis of rotation D1 that is oriented orthogonally to both force paths K1 and K2. For its part, the rotary bearing 5 is securely anchored via an attachment 6 with the unit 2 that is to be damped. At a distance r from the rotary bearing 5, extending from the first axis of rotation D1, the lever 4 is mounted on a second rotary bearing 7 such that it can rotate about a second axis of rotation D2, which is oriented in parallel to the first axis of rotation D1. The second rotary bearing 7 is securely anchored via an attachment 8 with the vibrating unit 1. A massive body 9 is attached on the end of the lever arm 42 that is mounted such that it can freely vibrate, and is opposite to the end of the lever arm 41, which end of the lever arm 42 is distanced from the first axis of rotation D1 by the lever arm length R. The body 9 is mounted such that it can pivot in two directions about the axis of rotation D2, and, as a function of the acceleration acting at the location of the body, generates an inertial force FT acting along the second force path K2 in the direction of deflection. It is necessary to select the inertial force FT that can be introduced along the second force path K2 with respect to magnitude, frequency and phase such that the inertial forces FT acting along the second force path K2 fully compensate for, and thus eliminate, the resonance forces Fres acting in the event of resonance along the first force path K1 via the support spring 3 between the resonantly vibrating unit 1 and the unit 2 that is to be damped. The mode of operation that underlies the force generator, which is designed as a lever mechanism, thus operates so that the lever mechanism as a function of its inertia is set into anti-resonance compared with the resonant vibration behavior of the vibrating unit 1. As a result of the dynamic component of the spring force Fres and the dynamic force being generated by the force resonator, by virtue of the relative movement between the vibrating unit 1 and the unit 2 that is to be damped, act in opposition and with equal strength at the location of the center of gravity 2s of the unit 2 that is to be damped. Thus a maximum isolation of vibration between the vibrating unit 1 and the unit 2 that is to be damped is present at a fixed prescribed resonant frequency, to which the anti-resonance frequency of the force generator is set by the adjustment of particular parameters describing the kinematics of the lever mechanism. To this end it is in particular necessary to coordinate the following parameters with one another: the mass of the unit 2 that is to be damped, the mass of the massive body 9, the spring stiffness k of the at least one support spring 3, the lever ratio QR=R/r, and the massive moment of inertia J of the lever arm 4.